Annular dowel for timber bonds



March 21, 1933. J. SEGER ANNULAR DOWEL FOR TIMBER BONDS Filed Sept. 11, 1930 Patented Mar. 21 1933 UNITED STATES,

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moon SEGER, or zunrcn, SWITZERLAND, nssrenon rornn FIRM 1900111 13 a cm; '01? ZURICH, SWITZERLAND ANNULAR DOWEL r03 rmnnit nouns Application filed September 11, 1930. Serial No. 481,297.

This invention relates to annular dowels for timber bonds, i. e. for system points of lattice work, systems of dowelled beams and.

the like. Preferably the outer circumference of the ring is cylindrical and the inner circumference tapering down from the middle plane of the ring towards both ofits end faces. a

For obtaining a certain elasticity of the annular dowel and compensating internal stresses in the wood it has been, heretofore proposed to provide dowels of this type with an axial slot. This measure, however, was found to be objectionable as it caused the wood to spring which particularly at the joints is undesirable.

The object of the present invention is to avoid this drawback by constructing the annular dowel according to the invention in two parts.

With this arrangement both abutting faces of both halves of the ring may be plane or p the two abutting faces may be S-shaped respectively, so as to form an overlapping hinge-like joint, for thering halves. In both cases the abutting. faces extend parallel to each other. i The elasticity of a bipartite annular dowel of this type and its ability to adapt'itself to the deformations of the wood is obviously much greater than in the case of an integral Thereby, the annular dowel adjusts itself without causing internal stresses.

In the drawing a constructional form of the invention is illustrated, by way of example only, in which 'Fig. 1 is an end view of an annular dowel,

Fig. 2 is a section on the line II-II in Fig. 1;

Fig. 3 is an elevation of a timber bond with the dowel applied thereto, and

Fig. 4 is a section on the line IV.-IV in Fig. 3. 7

Referring to the drawing, 1 denotes a bipartite annular dowel having an outer cylindrical circumference 2 and an inner circumference 3 which is tapering down from the middle plane of the ring towards both of its end faces. The abutting faces 4 be- --notches in correspondence, the shape of the :the curved :abuttingfaces 5has the effect of :a hinge which transmits the respective substantial resistance to tendencies of the tween-the two halves .of .the ring, as shown on the right handsidein Fig. l,;are obliquely disposed to the radial direction and extend parallel to each other, whereas the abutting faces 5 shown on the opposite side of the ring areformed into S-shape the two surfaces beingcongruent curves or paralleldisposition; The S-shaped :faces form together axiallyextending sockets andpknobswhich interlock against overturning movement of the halves of the ring while offering no resistance to-opening and closing movements.

The. described bipartite ring is'inserted between the-'adjoiningtimbers'6, .7 (see Figs..-3 and 4 :.in such mannerthat the diameter through its joints vis perpendicular to the direction of extreme shrinkage in the wood of the timber juncture. For inserting the two rings 1 the timbers 6 and '7 are notched out atthe corresponding places,.so that the larger diameter of the notch is'madeequal "to the outer diameter of the apertured ring -and the inner diameter increases toward'the E-bottomsof the notches so that when corresponding'timbers are put :together with the two notches 1 together is substantially similar to a dowel ring, as shownintFig. 4:, and then ithe timberssarepressed together by meansof the-b01118. I

Under the influence of the forcesacting on :the ring .due to the shrinkage-of the wood the abutting faces of both halves of the ring close-oneachother, whereby'the joint with fthrusts to the. timbers without intermission at'this place, the-abuttingfacesof the ring joints overlapping each other, whilst the ring as a whole is nevertheless highly elastic. The -S shape of the hinge, whilepermitting opening and closing movements of: the halves of the ring without introducing internal secondary stresses, nevertheless offers a very halves to overturn individually.

The described annular dowel due to its" capability of yieldingly engaging the side portions of the groove in whichit is accommodated in the adjoining timbers of the name to this specification.

bond always receives the shear arising between these timbers under favorable conditions of loading which permits of keeping the amount of material applied to it down to a minimum. Thus the loading obtained for the dowel corresponds tothat of a cantilever supported at its thickest portion i. e., in the middle of the ring, with the bending mo ments decreasing towards the ends Owing to this fact the ends of the dowel can be reduced without impairing the strength thereof, wherein a saving of material is involved.

I claim 1. In a timber bond, the combination with grooves provided in'the surfaces of the timbers to'be joined,said grooves forming internal cores the sides of said'corestapering inward from the bottom of the grooves to the jointing surfaces of the, timbers, of a bipartite annular dowel having a cross-section corresponding to that ofthe juxtaposed grooves, the opposite. faces of the dowel joints being parallel and at least one of said joints S-shaped, the ends of the'two parts at the S-shaped joint being formed with interlocking axially extending sockets and knobs permitting opening and closing movements while opposing separate overturning move-.

ments of the. two parts, and tightening means for said timbers adapted topress said dowel home in said grooves so as to yieldingly engage the side portions of said grooves. v

2. In a timber bond, the combination with grooves provided in the surfaces of the timbers to be joined, said grooves forming in ternal cores and the sides of the cores taper-' ing inward from the bottom of the grooves to the jointing surfaces of the timbers, of a bipartite annular dowel having a cross-section corresponding to that of the juxtaposed grooves, the opposite faces of the dowel joints being parallel and one-joint plane and obliquely disposed to the radial direction and the other dowel joint S-shaped, the ends of the two parts at the S-shaped joint being formed with interlocking axially, extending sockets and knobs permitting opening and closing movements while opposing separate overturning movements of the two parts, and tightening means for said timbers adapted to press said dowelhome'in said grooves so as to yieldinglyengage the side portions of said grooves.

In-testimony whereof, I have signed my JACOB sEo'ER. 

